Striking device for stringed musical instruments



May 14, 1929. c. F. STODDARD STRIKING DEVICE FOR STRINGED MUSICAL INSTRUMENTS Filed Nov. 1, 1923 INVENTOR s fi'foddara.

Patented May 14, 1929.

UNITED STATES CHARLES F, STODDARD, OF NEW YORK, N. Y.

STRIKING DEVICE FOR STRING-ED MUSICAL INSTRUMENTS.

Application filed November .This invention relates to stringed musical instruments and has as one of its objects the provision of a simple and effective means for striking the strings of a stringed musical instrument'to produce musical sounds therefrom. Y

Other objects and advantages of the invention will appear hereinafter.

A preferred embodiment of the invention has been select-ed for purposes of illustration herein and is shown diagrammatically in the accompanying drawings, in which,

Figure 1 is a diagrammatic side elevation, partly in section, and 2 Figure 2 is a section on the line 22 of Figure 1.

It is to be understood in the following description of the invention, that the illustrative embodiment shown in the drawings is more or less diagrammatic and that the re ative positioning of the parts shown in the drawing is entirely arbitrary. It is proposed to insert the mechanisms described in a piano, however, in which case it is to be understood that the various parts, which will be described as fixed, may be fixed to any convenient portion of a piano structure.

Referring to the drawings, a hammer 1 pivoted freely at 2 in such manner that clockwise rotation of the same will cause it to strike a string 3 secured to a piano frame in the usual or in any suitable manner. An electro-magnet is'provided to actuate the hammer, a solenoid 4 being illustrated in the present embodiment, and an armature 5 is secured to the hammer adjacent the solenoid and arranged to cooperate therewith. A battcry 6 is provided as a suitable source of power for energizing the solenoid and is placed in a circuit 7 controlled by a switch 8. It will be apparent that when the switch 8 is positioned to close the circuit, the solenoid l will be energized and the hammer will be drawn forward to strike the string.

Means are provided f or operating the switch 8, the particular means shown for purposes of illustrationcomprising a simple pneumatic valve mechanism 9. The valve mechanism consists of an exhaust chamber 10 connected to a suitable source of exhaust by a tube 11, a valve chamber 12 and a diaphragm chamber 13. A diaphragm 14lseparates the diaphragm chamber and the exhaust chamber, and a port 15 connects the exhaust chamber to the valve chamber. An

' through Serial no. 672,049.

additional port 16 connects the valve chamber to atmospheric air. A bleed passage 17 allows the diaphragm chamber to be exhausted from the exhaust chamber 10 above.

A valve 18 controls the passage of air through the ports 15 and 16 and is mounted on a stem 19 which extends downwardly to be operated by the diaphragm 14 and extends upwardly above the valve through the port 16 to contact with the switch 8.

Under normal conditions with the valve mechanism inactive the parts will be positioned as shown in Figure 1, the exhaust chamber 10 being under exhaust, the valve chamber 12 being open to atmospheric air the port 16, and the diaphragm chamber 13 under exhaust through the bleed passage 17. Since the pressure in the exhaust chamber and the diaphragm chamber is equalized by the bleed, the valve will seat over the port 15.

For operating the valve, a. passage 20 is provided leading into the diaphragm chamber 13 which may be connected to a tracker bar 21 over which is passed in the usual manner a note sheet 22 having openings 23 therein. As will be apparent, when an imperforate part of the sheet covers the tracker opening 2% to which the tube 20 is coin nected, the valve mechanism will remain in the position shown in Figure 1. If one of the note sheet openings 23 passes over the tracker opening 24, however, atmospheric air will be admitted to the tube 20 which will disturb the equilibrium established by the bleed 17, thus causing the diaphragm 1st to rise carrying with it the valve 18. The upper extension of the valve stem 19 will at the same time cause the switch 8 to rise to close the circuit 7, thus energizing the solc noid and causing the hammer to be thrown forward to strike the string as before explained.

It may be desirable that means be provided for lifting the damper in synchronism with the movement of the hammer to strike the string in order that when the string has been struck it may be free to vibrate. A pneumatic 31 is provided having a fixed leaf 32 and a movable leaf 33 secured to the damper. A tube 34 is connected by a T joint 35 with a tube 36 leading into the valve chamber 12. When the valve 18 is in the position shown in Figure l the valve chamber is open to atmosphere and the pneumatic 31 will therefore also be open to atmosphere and will be expanded under the influence of the spring 37 to hold the damper against the string. Vhen the valve is raised, the valve chamber is exhausted from the exhaust chamber 10 while the inflow of atmosphere is stopped by the contact of the valve against the port 16 and the pneumatic 31 will be collapsed, therefore, and the resulting movement of the movable leaf 83 toward the fixed leaf 32 will withdraw the damper from the string.

It will be observed that this action will take place synchronously with the closing of the circuit 7 to actuate the hammer so that while the hammer is advancing to strike the string the damper is being retracted to leave the string free to vibrate.

A tube 40 is also connected to the T joint 35 and is thereby connected pneumatically with the valve chamber 12. This tube leads to a block 41 on which pivoted a circuit breaker 42 having an annular groove 43 formed in one face thereof into which the tube 40 opens. An arm 44 extends upwardly from the circuit breaker and is connected to a coil spring 45 which holds itnormally in position to touch the contact 46 to complete the circuit 7. A cord 47 is connected to the arm 44 and is also connected to the shank of the hammer 1 at 48.

As the hammer is thrown forward under the influence of the solenoid 4 to strike the string, the cord 47 will pull taut just prior to the time of actual contact of the hammer with the string. The arm 44 will be pulled in a clockwise direction and the circuit 7 will be broken, thus tie-energizing the solenoid 4 and permitting the hammer 1 to rebound immediately from the string. If desired, the return of the hammer may be as sisted by a spring 49 secured to the hammer shank. Previous to the time the circuit is broken, air has been exhausted from the tube 40 and from the annular groove 43 due to the rising of the valve 18, thus holding the circuit breaker 42 firmly against the block 41, the friction thereby established between the two preventing the return of the arm 44 under the influence of the spring 45.

After the note sheet opening has passed the tracker opening, the valve 18 is permitted to drop, the switch 8 drops and opens the circuit 7. The suction on the brake 42 is released at the same time and the arm 44 is drawn back by the spring 45 to again contact at 46.

It will be observed that one effect of the foregoing action will be to cause the hammer to strike a blow to the string, as distinguished from av pressure stroke, due to the fact that the actuating means is deenergized just prior to the time at which the string is struck. The hammer therefore strikes the string through the force of its inertia or momentum induced by said actuating means, the actuating means itself being deenergized at the time the blow is struck. These blows may be repeated with any necessary rapidity and may also be subjected to complete control no matter what the force of the blow may be.

An electro-magnet 51 is included in the circuit 7 to actuate a latch 52 pivoted at 53. The latch is normally drawn downwardly toward a stop 54 by a spring 55 and in this position it engages a groove 56 in the hammer to retain the hammer in inoperative position. Since the electro-magnet 51 is included in the circuit 7, it will be ener ized so at any time that the circuit 7 is closed, or, in other words, whenever the electro-magnet 4 is energized to actuate the hammer, the electro-magnet 51 is also energized to raise the latch to release the hammer. At the same time that the electro-magnet 4 is deenergized, the clectro-magnet 51 is de-energized. the latch 52 is dropped against its stop, and when the hammer reaches its position of rest against the rest rail 60, the latch will engage the groove 56 to prevent a counter rebound of the hammer.

The mechanisms thus far described are in themselves completely operative as mechanisms to strike a string of a musical instrument to produce a sound therefrom. The sounds produced, however, would all be of approximately the same intensity. In order, therefore, to improve the musical quality of the device, expression mechanisms are provided by which the degree of power applied to the hammers may be varied to thereby vary the force of the blows to the strings.

For this purpose resistance elements 61, 62 and 63 are incorporated in the circuit 7 which elements are preferably of varying resistance capacity. The sum of the resistances should be such that the current passing through the circuit 7 under what may be termed normal conditions, that is, when the current passes through all of the resistance elements, will be just sufficient to cause a note to be sounded at the minimum intensity at which it is desired to play.

Means are provided comprising the pneumatic valves 64, 65 and 66 to selectively cut out of the circuit 7 any desired resistance element to thereby vary the total resistance in the circuit 7. The valves 64, 65, and 66 may be of any ordinary construction, sim- 12o ilar for instance to the valve mechanism 9 hercinbefore described. The valves are connected by tubes 67, 68 and 69 with tracker openings 70, 71 and 72 respectively. Switches 73, 74 and 75 are provided to cooperate with the valve stems 76, 77 and 78 by which they are adapted to be operated.

\Vhen it is desired that a note shall be played of softest intensity, the current passing through circuit 7 allowed to pass through all. of the resistance elements 61, 62 and 63. When it is desired that a note shall be played at greater intensity, one or more of the resistance elements are cut out of the circuit 7 by operation of the valves 64,65 and 66 by suitable openings in the note sheet. By giving the resistance elements different values, as for instance, the arbitrary values 1, 2 and i, it will. be apparent that by combining various ones, numerous intensity values may be secured.

In operation, as the note sheet passes over the tracker bar, and perforations therein register with the openings 23, the valve mechanism 9 is operated and the switch 8 raised to close the circuit 7. The closure of this circuit causes the solenoid to be energized to actuate the han'imer to strike the string. The closing of the circuit 7 also causes the electro-magnet 51 to be energized to raise the latch 52 to allow the hammer 1 to be actuated. synchronously with these actions the pneumatic 31 is collapsed to withdraw the damper from the string.

Just. prior to the actual striking of the string by the hammer, the circuit '7 is broken by the movement of the arm 44 by the harm Iner, the hammer having previously gained sufficient momentum, however, to enable it to, complete its stroke and strike the string. The circuit 7 remains broken so long as the note sheet opening is over the tracker opening due to thetact that the friction on the circuit breaker 42' caused by suction on groove 43 retains the arm 44 in position to break the circuit. As the hammer rebounds it" is caught and held by the latch 52 to prevent rebound.

The expression mechanismsare controlled by the note sheet and tracker bar. Under normal conditions with all of the expression tracker openings closed by an imperiorate part of the note sheet, the instrument will play at softest intensity. If it is desir d to increase the intensity, various combinations may be made to cut out the resistance elements 61, ,62 and 63 to thereby vary the amount of current passing through the circuit 7 and hence the force of the blow struck to the string.

It is to be understood of course that the mechanisms described herein for striking the string may be duplicated as necessary in order to provide a striking mechanism for each string of the instrument. It will also be apparent, however, that a single set of expression mechanisms as described may control the expression of a plurality of striking mechanisms.

It is to be understood that the invention is not limited to the embodiment herein shown for purposes of illustration but that on the contrary it may be variously modified and embodied within the scope of the subjoined claims.

I claim as my invention l. A device for striking a string of a musicalinstrument con'iprising, a hannncr,a dam per, electro-inagnetic means tor actuating the lmnnner to strike the string, pueun'iatic means for actuating the damper, and com mon means for controlling said actuating means.

2. A device for striking a string of a musical instrument comprising, a hammer, a damper, means for actuating the hammer to strike the string, separate pneumatic means to actuate the damper, and common means for controlling said actuating means.

3. A device for striking a string of a musical instrument comprising, a hammer, electro-magnetic means to actuate said hammer to strike a string, and pneumatic means to control said electro-magnetic means.

et. A device for striking a string of a musical instrument, comprising, a hammer, means to actuate said hammer to strike a string, a latch to retain said hammer in inoperative position, and means to release said latch in synchronism with said hammer actuating means.

5. A device for striking a string of a musical instrument, comprising a hammer, electro-magnetic means to actuate said hammer strike a string, including an electric circuit, and means to closeand break said circuit, a latch to retain said hammer in inoperative position and electromagnetic means to release said latch including an electric circuit connected to said first circuit, whereby said hammer and latch releasing means may be operated in synchronism.

, 6. A device for striking a string of a musical instrument comprising, a hammer, a damper, means for actuating the hammer to strike the string, separate means to actuate the damper, common means for controlling said actuating means, and means for de-energizing said hammer actuating means while said damper actuating means remains in operation.

7. A device for striking a string of a musical instrument comprising, a hammer, a damper, means for actuating the hammer to strike the string, separate means to actuate the damper, common means tor controll ng said actuating means. an d hammer controlled means for de-energizing said. hammer actuating means while said damper actuating means remains in operation.

8. A device for striking a string of a musical instrument comprising, a hammer, a damper, electro-magnetic means for actuating the hammer to strike the string, pneumatic means for actuating the damper, common means for controlling said actuating means, and means for de-energizing said hammer actuating means while said damper actuating means remains in operation.

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9. A device for striking a string of a musical instrument comprising, a hammer, a damper, electro-magnetic means for actuating the hammer to strike the string, pneumatic means for actuating the damper, common means for controlling said actuating means, and hammer controlled means for de-enengizing said hammer actuating means'while said damper actuating means remains in operation.

10. A device for striking a string of a musical instrument comprising, a hammer, a damper, means for actuating the hammer to strike the string, separate means to actuate the damper, common means for controlling said actuating means, means for (lo-energizing said hammer actuating means while. said damper actuating means remains in operation, and means to retain said de-energizing means in released position.

11. A device for striking a string of a musical instrument comprising, a hammer, a damper, means for actuating the hammer to strike the string, separate means to actuate the damper, common means for controlling said actuating means, means for (lo-energizing said hammer actuatingmeans while said damper actuating means remains in operation, and means controlled by said common controlling means for retaining said de-energizing means in released position.

12. A device for striking a string of a musical instrument comprising, a hammer, a damper, electro-magnetic means for actuating the hammer to strike the string including an electric circuit and means for closing said circuit, pneumatic means to actuate the damper, common means for controlling said actuating means, means for breaking said circuit to de-energize said hammer actuating means while said damper actuating means remains in operation, and pneumatic means to retain said de-energizing means in released position.

13. A device for striking a string of a musical instrument comprising, a hammer, a damper, electro-magnetic means for actuating the hammer to strike the string including an electric circuit and means tor closing said circuit, pneumatic means to actuate the damper, common means for controlling said actuating means, hammer controlled means for breaking said circuit to deenergize said hammer actuating means while said damper actuating means remains in operation, and pneumatic means to retain said de-energizing means in released position. p

14. A musical instrument comprising, in combination, sound producing strings, hammers for striking said strings, dampers, electro-magnetic means for actuating the hammers to strike the strings, pneumatic means for actuating the dampers, common means for controlling said actuating means,

and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

15. A musical instrument comprising, in combination, sound producing strings, ham.- mers for striking said strings, dampers, means for actuating the hammers to strike the strings, separate means to actuate the dampers, common means for controlling said actuating means, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

16. A musical instrument comprising, in combination, sound producing strings, hammers for striking said strings, electro-magn etic means toactuate said hammers to strike the strings, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

17. A musical instrument comprising, in combination, sound producing strings, hammers for striking said strings, dampers, electro-magnetic means for actuating the hammers to strike the strings, pneumatic means for actuating the dampers, common means for controlling said actuating means, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

18. A musical instrument comprisin in con'ibination, sound producin strings, 1aminers for striking said strings, means to actuate said hammers to strike the strings, means to de-energize said actuating means to permit the hammers to rebound from the strings, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

19. A musical instrument comprising, in combination, sound producing strings, hammers for striking said strings, electro-magnetic means to actuate said hammers to strike the strings including an electric circuit, means to close said circuit to actuate the hammers, separate means to break said circuit to permit the hammers to rebound from the strings, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

20. A musical instrument comprisin in combination, sound producing strings, am- -mers for striking said strings, means to actuate said hammers to strike the strings, means to control said actuating means, means to de-energize said actuating means to permit the hammers to rebound from the strings, means to retain said tie-energizing means in open position, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

21. A musical instrument comprising, in combination, sound producing strings, hammers for striking said strings, eleotro-magnetic means to actuate said hammers to strike the strings including an electric circuit, means to close said circuit, means to control said actuating means, means to break said circuit to permitthe hammers to rebound from the strings, means to retain said circuit breaking means in open position, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

22. A musical instrument comprising, in

combination, sound producing strings, hammers for striking said strings, electro-magnetic means to actuate said hammers to strike the strings including an electric circuit, means to close said circuit, means to control said actuating means, hammer con trolled means to break said circuit to permit the hammers to rebound from the strings, means controlled by said first controlling means to retain said circuit breaking means in open, position, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

23. A musical instrument com 'n'ising, in combination, sound producing strings, hammers for striking said strings, means to actuate said hammers to strike the strings, latches to retain said hammers in inoperative position, means to release said latches in synchronism with said hammer actuating means, and means to vary the power applied to said hammers whereby the i1 ensity ot the notes sounded may be varied.

24. A musical instrun'ient comprising, in combination, sound producing strings, hanr mers for striking said strings, electro-magnetic means to actuate said hammers to strike the strings, including an electric circuit, means to close and break said circuit, latches to retain said hammers in inoperative position, electro-magnetic means to release said latches including an electric circuit connected to said first circuit, whereby said hammer and latch releasing means may be operated in synchronism, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

25. A musical instrument comprising, in combination, sound producing strings, hammers "for striking said strings, dampers, means for actuating the hammers to strike the strings, separate means to actuate the dampers, .common means for controlling said actuating means, hammer controlled means for de-energizing said hammer actuating means while said damper actuating means remains in operation, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

' 26. A musical instrument comprising, in combination, sound producing strings, hammers for striking said strings, dampers, means for actuating the hammers to strike the strings, separate means to actuate the dampers, I common means for controlling said actuating means, means for de-energizing said hammer actuating means while said damper actuating means remains in operation, means to retain said de-ener 'izing means in released position, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varied.

27. A musical instrument comprising, in combination, sound producing strings, hammers for striking said strings, dampers, electro-magnetic means for actuating the hammers to strike the strings including an electric circuit and means for closing said circuit, pneumatic means to actuate the dampers, common means for controlling said actuating means, means for breaking said circuit to tie-energize said hammer actuating means while said damper actuating means remains in operation, pneumatic means in said de-energlzmg means in released po.v j-ion, and means to vary the power applied to said hammers whereby the intensity of the notes sounded may be varier.

28. A musical instrument comprising, in combination, sound producing strings, ham mers for striking said strings, electro-magnetic means to actuate said hammers to strike the strings, electrical resistance means to control the DO'WOI. applied to said hammers, a tracker, and tracker controlled means to vary the capacity oi. said electrical resistance to thereby vary tone intensitics.

29. A musical instrument comp; isin in combination, sound producing strings, hammers for striking said strings, moans teactuate said hammer s without mechanical contact therewith, elertl ir -l resistance means to control the power appned to said hammers, a tracker, and tracker controlled means to vary the capacity of said electrical resistance to thereby vary tone intensities.

3 A musical instrument comprising, in combination, sound producing strings, hammers for striking said strings, eiectro-nmgnetic means to actuate said hammers to strike the strings, a plurality of electrical resistance elements to control the power ap- 'ed to said hammers, and tracker controlled pueumatic means to selectively cut out one or more of said resistance elements to thereby vary tone intensities.

31. A musical instrument comprising, in combination, sound producing strings, hammers for striking said strings, means to actuate said hammers without mechanical contact therewith, a plurality of electrical resistance elements to control the power applied to said nammers, and tracker c0ntrolled pneumatic means to selectively cut combination, sound producing strings, hammers for striking said strings, armatures on said hammers and elect-ro-magnetic means to actuate said arn'iatures and hammers, a plurality of electrical resistance elements to control the power applied to said hammers, and tracker controlled pneumatic means to selectively cutout one or more of said resistance elements to thereby vary tone intcnsities.

In testimony whereof, I have signed my 25 name to this specification this 30th day of October, 1923.

CHARLES F. STODDARD. 

